FreeBSDOperating system
CVE-2020-7464
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn FreeBSD 12.2-STABLE before r365730, 11.4-STABLE before r365738, 12.1-RELEASE before p10, 11.4-RELEASE before p4, and 11.3-RELEASE before p14, a programming error in the ure(4) device driver caused some Realtek USB Ethernet interfaces to incorrectly report packets with more than 2048 bytes in a single USB transfer as having a length of only 2048 bytes. An adversary can exploit this to cause the driver to misinterpret part of the payload of a large packet as a separate packet, and thereby inject packets across security boundaries such as VLANs.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceIn FreeBSD's ure(4) USB Ethernet driver for Realtek adapters, a programming error causes packets exceeding 2048 bytes to be incorrectly reported as exactly 2048 bytes. This allows an attacker to inject packets by manipulating the driver into misinterpreting portions of oversized packets as separate, legitimate packets, enabling cross-VLAN injection and bypassing network segmentation.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
FreeBSDOperating system
= 11.3= 11.4= 12.1= 12.2CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify FreeBSD versionRun 'freebsd-version -k' to get the kernel version or 'uname -r' to get the release versionAffected if Version matches 11.3, 11.4, 12.1, or 12.2
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Check if ure driver is loadedRun 'kldstat | grep ure' or check /boot/kernel if ure.ko existsAffected if The ure(4) driver module is loaded or present on the system
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Identify Realtek USB Ethernet interfacesRun 'ifconfig -a' and look for ue* interfaces, then run 'usbdevs -v' to identify Realtek-based USB Ethernet adaptersAffected if A Realtek USB Ethernet adapter is configured and using the ure driver
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Verify oversized packet handlingThis requires packet capture analysis; capture traffic on the ue interface and check if packets larger than 2048 bytes are being incorrectly reported as exactly 2048 bytes in the captureAffected if Packets exceeding 2048 bytes appear as exactly 2048 bytes in captures, indicating the driver misreports packet size
The system is affected if it runs FreeBSD 11.3, 11.4, 12.1, or 12.2 AND uses a Realtek USB Ethernet adapter via the ure(4) driver, with oversized packets being misreported as exactly 2048 bytes.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply the appropriate FreeBSD security patch (r365730 for 12.2-STABLE, r365738 for 11.4-STABLE, p10 for 12.1-RELEASE, p4 for 11.4-RELEASE, or p14 for 11.3-RELEASE) or upgrade to a patched version. For systems unable to patch immediately, consider using alternative network interfaces or network segmentation to limit exposure.
Fix this in FreeBSD
Scoped from the published advisory
- Consultation2.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,040.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-7464 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-7464 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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